1. Technical Field
The present invention relates to a heat transport device and a projector having a heat transport device.
2. Related Art
According to the related art, a loop heat pipe is known as a cooling device used for various electronic devices. The loop heat pipe is configured of an evaporating unit which evaporates a hydraulic fluid with the heat from a heat generating body, a condensing unit which radiates the heat of the evaporated hydraulic fluid and thus condenses the vapor, and a vapor pipe and a liquid pipe which connect the evaporating unit and the condensing unit in the shape of a loop. The loop heat pipe like this takes time to start up because a cooling cycle is not established until the hydraulic fluid present in the vapor flow path within the evaporating unit is completely evaporated.
JP-A-2012-255577 discloses a technique in which a temperature difference is provided between the vapor pipe and the liquid pipe, thus reducing the startup time of the loop heat pipe. WO2011/061952 discloses a technique in which the vapor pipe is heated to eliminate the liquid in the vapor pipe, thus reducing the startup time of the loop heat pipe.
However, the technique of JP-A-2012-255577 has some problems such as the need for a heat storage material other than the loop heat pipe and the difficulty in coping with the case where the amount of heat generated is variable. Meanwhile, the technique of WO2011/061952 prevents condensation within the vapor pipe by heating the vapor pipe with a heating device. However, this technique is not very promising in terms of reduction in startup time, though the technique contributes to stable operation of the loop heat pipe.
If the loop heat pipe takes time to start up, there is a problem that the heating temperature of an electronic component as a cooling target may overshoot. Also, if the amount of heat generated by the electronic component is small or if there is a large influence of heat leak or the like, there is a problem that the loop heat pipe does not start up.
Thus, a heat transport device which reduces the startup time of the loop heat pipe, and a projector having a heat transport device are demanded.